Combustion furnaces for burning pulverized fuel such as pulverized coal fed from Powder supply apparatus is known as combustion furnaces used in blast furnace facilities, thermal power plants, and the like. In such a combustion furnace, pulverized fuel is sprayed thereinto together with air and burnt therein. Such a burning method using pulverized coal is widely used because coal itself is highly combustible.
A gas-carried Powder supply apparatus that conveys pulverized fuel with carrier gas is known as a Powder supply apparatus for supplying pulverized fuel to the combustion furnace. In such a Powder supply apparatus, pulverized fuel in a feed tank is fed to a powder delivery pipe and conveyed by the carrier gas therein. The supply rate of the pulverized fuel into the powder delivery pipe may be controlled according to the aperture of a valve for powder provided near an outlet in a bottom portion of a feed tank.
In addition, in order to allow powder to be easily fed from the feed tank to outside thereof, a Powder supply apparatus in which fluidizing gas is introduced into a feed tank and powder in the feed tank is fluidized by the fluidizing gas is known.
In a Powder supply apparatus disclosed in Patent Document 1 listed below, fluidizing gas is introduced into a feed tank as mentioned above and fluidized powder is fed from the feed tank. The supply rate of the fluidized powder is controlled according to the aperture of a valve for powder as described above.